Role of Computerized Physician Order Entry Systems in Facilitating Medication Errors

Context Hospital computerized physician order entry (CPOE)systems are widely regarded as the technical solution to medicationordering errors, the largest identified source of preventablehospital medical error. Published studies report that CPOE reducesmedication errors up to 81%. Few researchers, however, havefocused on the existence or types of medication errors facilitatedby CPOE.

Objective To identify and quantify the role of CPOE infacilitating prescription error risks.

Design, Setting, and Participants We performed a qualitativeand quantitative study of house staff interaction with a CPOEsystem at a tertiary-care teaching hospital (2002-2004). Wesurveyed house staff (N = 261; 88% of CPOE users);conducted 5 focus groups and 32 intensive one-on-one interviewswith house staff, information technology leaders, pharmacy leaders,attending physicians, and nurses; shadowed house staff and nurses;and observed them using CPOE. Participants included house staff,nurses, and hospital leaders.

Main Outcome Measure Examples of medication errors causedor exacerbated by the CPOE system.

Results We found that a widely used CPOE system facilitated22 types of medication error risks. Examples include fragmentedCPOE displays that prevent a coherent view of patients’medications, pharmacy inventory displays mistaken for dosageguidelines, ignored antibiotic renewal notices placed on papercharts rather than in the CPOE system, separation of functionsthat facilitate double dosing and incompatible orders, and inflexibleordering formats generating wrong orders. Three quarters ofthe house staff reported observing each of these error risks,indicating that they occur weekly or more often. Use of multiplequalitative and survey methods identified and quantified errorrisks not previously considered, offering many opportunitiesfor error reduction.

Conclusions In this study, we found that a leading CPOEsystem often facilitated medication error risks, with many reportedto occur frequently. As CPOE systems are implemented, cliniciansand hospitals must attend to errors that these systems causein addition to errors that they prevent.INTRODUCTION

Adverse drug events (ADEs) are estimated to injure or kill morethan 770 000 people in hospitals annually.1 Prescribingerrors are the most frequent source.2-5Computerized physicianorder entry (CPOE) systems are widely viewed as crucial forreducing prescribing errors2-3,6-17 and saving hundreds of billionsin annual costs.18-19 Computerized physician order entry systemadvocates include researchers, clinicians, hospital administrators,pharmacists, business councils, the Institute of Medicine, statelegislatures, health care agencies, and the lay public.2-3,6-10,12,14-17,20-22 These systems are expected to become more prevalentin response to resident working-hour limitations and relatedcare discontinuities23 and will supposedly offset causes (eg,job dissatisfaction) and effects (eg, ADEs) of nursing shortages.24-25Such a system is increasingly recommended for outpatient practices(Box).

Adoption of CPOE perhaps gathered such strong support becauseits promise is so great, effects of medication error so distressing,circumstances of medication error so preventable, and studiesof CPOE preliminary yet so positive.21, 26-28 Studies of CPOE,however, are constrained by its comparative youth, continuingevolution, need to focus on potential rather than actual errors,and limited dissemination (in 5% to 9% of US hospitals).29-36Two critical studies21, 30 examined distinctions between reductionsin possible ADEs vs actual reductions in ADEs; the former arewell documented and often cited, but the latter are largelyundocumented and unknown. Studies of CPOE efficacy (17% to 81%error reduction) usually focus on its advantages2-3,6-11,14-16and are generally limited to single outcomes, potential errorreduction, or physician satisfaction.28, 30, 34-40 Often studiescombine CPOE and clinical support systems in their analyses.30,40-41

We performed a quantitative and qualitative study incorporatingstructured interviews with house staff, pharmacists, nurses,nurse-managers, attending physicians, and information technologymanagers; real-time observations of house staff writing orders,nurses charting medications, and hospital pharmacists reviewingorders; focus groups with house staff; and written questionnairesadministered to house staff. Qualitative research was iterativeand interactive (ie, interview responses generated new focusgroup questions; focus group responses targeted issues for observations).

Setting

We studied a major urban tertiary-care teaching hospital with750 beds, 39 000 annual discharges, and a widely used CPOEsystem (TDS) operational there from 1997 to 2004. Screens wereusually monochromatic with pre-Windows interfaces (EclipsysCorp, Boca Raton, Fla). The system was used on almost all servicesand integrated with the pharmacy’s and nurses’ medicationlists.

This study was approved by the University of Pennsylvania institutionalreview board. The researchers were not involved in CPOE systemdesign, installation, or operation.

Survey. From 2002 to the present, we distributed structured,self-administered questionnaires to house staff who order medicationsvia CPOE. The 71-item questionnaire focused on working conditionsand sources of error and stress. We report here on 10 CPOE-relatedquestions. We constructed the survey after our interviews andfocus groups, leading us to provide separate answer optionsabout sources of error and sources of stress; add questionson CPOE as a possible source of error risk, an issue that emergedin our qualitative research; and quantify the frequency of theseerror risks. Not all CPOE-related error risks are amenable tosurvey questions. We have robust survey results on 10 of the22 identified error risks; these findings are presented withthe qualitative findings.

More than 70% of the questionnaires were administered at routinehouse staff meetings. Other house staffwere located via departmentalcoordinators or pagers. Participants received $5 coupons forlocal coffee shops. Two hundred sixty-one house staff (88% ofthe target population) completed the questionnaire.

Characteristics of the house staff were as follows. Of 94 internscontacted, 85 (90.4%) participated; of 96 second-year residents,84 (87.5%) participated; and of 107 third- through fifth-yearresidents, 92 (85.9%) participated. The participating samplewas 44.8% female, 66.3% white, and 32.5% were interns. Participants’ mean age was 29.6 years. These data did not differ significantlyfrom characteristics of nonparticipants.

Our qualitative and quantitative research identified 22 previouslyunexplored medication-error sources that users report to befacilitated by CPOE. We group these as (1) information errorsgenerated by fragmentation of data and failure to integratethe hospital’s several computer and information systemsand (2) human-machine interface flaws reflecting machine rulesthat do not correspond to work organization or usual behaviors.

Information Errors: Fragmentation and Systems Integration Failure

Assumed Dose Information. House staff often rely on CPOE displaysto determine minimal effective or usual doses. The dosages listedin the CPOE display, however, are based on the pharmacy’swarehousing and purchasing decisions, not clinical guidelines.For example, if usual dosages are 20 or 30 mg, the pharmacymight stock only 10-mg doses, so 10-mg units are displayed onthe CPOE screen. Consequently, some house staff order 10-mgdoses as the usual or “minimally effective” dose. Similarly,house staff often rely on CPOE displays for normal dosage ranges.

House staff regularly use CPOE to determine dosages (Table).In the last 3 months, 73% of house staff reported using CPOEdisplays to determine low doses for medications they did notusually prescribe; 82% used CPOE displays to determine rangeof doses (Table). Two fifths (38%-41%) used CPOE displays todetermine dosages at least a few times weekly; 10% to 14% usedCPOE displays in this misleading way daily.

Medication Discontinuation Failures. Ordering new or modifyingexisting medications is usually a separate process from canceling(“discontinuing”) an existing medication. Without discontinuingthe current dose, physicians can increase or decrease medication(giving a “double” total dose, eg, every 6 hours and every 8hours), add new but duplicative medication, and add conflictingmedication. Medication-canceling ambiguities are exacerbatedby the computer interface and multiple-screen displays of medications;as discussed below, viewing 1 patient’s medications mayrequire 20 screens.

Discontinuation failures “for at least several hours” from notseeing patients’ complete medication records were reportedby 51% (Table). Twenty-two percent indicated that this failureoccurs a few times weekly, daily, or more frequently.

Immediate Orders and Give-as-Needed Medication DiscontinuationFaults. NOW (immediate) and PRN (give as needed) orders maynot enter the usual medication schedule and are seldom discussedat handoffs. Also, because medication charting is so cumbersomeand displays so fragmented, NOW and PRN orders are less certainto be charted or canceled as directed. Failure to chart or cancelcan result in unintended medications on subsequent days or reordering(duplications) on the same day.

Antibiotic Renewal Failure. To maximize appropriate antibioticprescribing, house staff are required to obtain approval byinfectious disease fellows or specialist pharmacists. Lack ofcoordination among information systems, however, can producegaps in therapy because antibiotics are generally approved for3 days. Before the third day, house staff should request continuationor modification. To aid this process, reapproval stickers areplaced on paper charts on the second day. However, when housestaff order medications, they primarily use electronic charts,thus missing warning stickers. No warning is integrated intothe CPOE system, and ordering gaps expand until noticed. Someunintentional “gaps” continue indefinitely because it is unknownwhether antibiotics were intentionally halted. In the last3 months, 83% of house staff observed gaps in antibiotic therapybecause of unintended delays in reapproval. Twenty-seven percentreported this occurrence a few times weekly; 13%, once dailyor more frequently (Table).

Diluent Options and Errors. A recent CPOE innovation requireshouse staff to specify diluents (eg, saline solution) for administeringantibiotics. A few diluents interact with antibiotics, generatingprecipitates or other problems. Many house staff are unawareof impermissible combinations. Pharmacists catch many such errors,but their interventions are time-consuming and not ensured.

Conflicting or Duplicative Medications. The CPOE system doesnot display information available on other hospital systems.For example, only the pharmacy’s computer provides druginteraction and lifetime limit warnings. Pharmacists call housestaff to clarify questionable orders, but this additional stepcosts time and increases error potential. House staff and pharmacistsreported that this method generates tension.

Human-Machine Interface Flaws: Machine Rules That Do Not Correspond to Work Organization or Usual Behaviors

Patient Selection. It is easy to select the wrong patient filebecause names and drugs are close together, the font is small,and, most critical here, patients’ names do not appearon all screens. Different CPOE computer screens offer differingcolors and typefaces for the same information, enhancing misinterpretationas physicians switch among screens. Patients’ names aregrouped alphabetically rather than by house staff teams or rooms.Thus, similar names (combined with small fonts, hectic workstations,and interruptions) are easily confused.

Fifty-five percent of house staff reported difficulty identifyingthe patient they were ordering for because of fragmented CPOEdisplays; 23% reported that this happened a few times weeklyor more frequently (Table).

Wrong Medication Selection. A patient’s medication informationis seldom synthesized on 1 screen. Up to 20 screens might beneeded to see all of a patient’s medications, increasingthe likelihood of selecting a wrong medication.

Seventy-two percent of house staff reported that they were oftenuncertain about medications and dosages because of “difficultyin viewing all the medications on 1 screen.”

Unclear Log On/Log Off. Physicians can order medications atcomputer terminals not yet “logged out” by the previous physician,which can result in either unintended patients receiving medicationor patients not receiving the intended medication.

Failure to Provide Medications After Surgery. When patientsundergo surgery, CPOE cancels their previous medications. Whensurgeons order new or renewed medications, however, the ordersare “suspended” (not sent to the pharmacy) until “activated”by postanesthesia-care nurses. But these “activations” stilldo not dispense medications. Physicians must reenter CPOE andreactivate each previously ordered medication. Surgery residentsreported that they sometimes overlooked this extra process.